Interactive Learning Systems

First the IWB provides an active learning environment for all students. This means that the students are rarely involved in an interactive learning process. What is OSPF?Answer: OSPF is a link state routing protocol. OSPF routers exchange their Link State Advertisement (OSPF LSA) to learn interface IP addresses from each other. Each router saves its LSAs in its Link State Database (LSDB.) Neighboring nodes synchronize their LSDBs. With consistent LSDBs, OSPF routers are able to calculate shortest paths to reach destinations.

1) Each OSPF node creates a Router LSA to describe its interface IP addresses.

2) Routers discover neighbors by flooding Hello. What is Router LSA?Answer: Each OSPF router creates a Router LSA to describe its interfaces’ IP addresses. In a very simple OSPF network, only Router LSAs are needed to calculate shortest paths.

How can a router use LSDB to calculate routing paths?Answer:; From LSDB, an OSPF node learns the complete topology of the network: the number of routers being connected; Individual router’s interfaces and their IP addresses; Interface link costs (OSPF metric).

For example [a], in the OSPF simulation, R1′s LSDB contains two Router LSAs: